This invention relates to a fluid flow system with a vacuum breaker for use in faucet systems and particularly relates to a fluid flow system with an atmospheric vacuum breaker which is used in a faucet system to prevent the reverse flow of water from a contaminated source to a potable supply associated with the faucet system.
In one type of faucet system, a faucet spout is designed to support at its free end a removable water dispensing head which can function selectively to provide a stream of water therefrom in a stream mode or a spray of water therefrom in a spray mode. The dispensing head is connected to a flexible conduit which extends inwardly through the spout and is coupled to a potable water system through a valve of a conventional hot and cold water system.
In the stream mode, the valve is adjusted to provide the desired mix of hot and cold water which flows through the flexible conduit and exits as a water stream through the head which is supported at the end of the spout. In this manner, the head functions as a typical water-dispensing spout. When the head is used as a spray head in the spray mode, the head is removed from the spout and is pulled to draw the flexible conduit therefrom. A button on top of the head is depressed to adjust the head to function .in the spray mode whereafter the water is dispensed from the head in a spray.
Typically, a sink or basin is located below the spout and head. If, for example, dishes are washed in the sink, dirty and contaminated water will collect in the sink. If the head is placed in the dirty water in the sink during a period when the faucet valve is on and a negative pressure develops in the supply line, the dirty water could be drawn from the sink, through the head and flexible conduit, through the valve and into the supply line of the potable water system. Thereafter, if water is drawn from the supply line through any of the faucet systems in the house, a mix of contaminated and potable water will undesirably appear at the outlet or spout of the operated faucet systems. The negative pressure could develop, for example, because of a break in a main water line outside of the house or when a sudden and exceptional demand is placed on the main water supply such as by the fire department in extinguishing a fire nearby.
In the past, a variety of techniques have been employed to prevent the undesirable draw of contaminated water from the sink when negative pressure occurs in the supply line as described above. An example of one system for preventing the above-described reverse flow of water is disclosed in U.S. Pat. No. 4,696,322 which was issued to Alfons Knapp et al. on Sep. 29, 1987. In the faucet system disclosed in U.S. Pat. No. 4,696,322, a hollow spherical valve element is formed with water inlet ports to accommodate coupling to a hot water supply line and a cold water supply line. The valve element is further formed with an outlet port to facilitate supplying of a selected mix of hot and cold water therethrough.
As further illustrated in U.S. Pat. No. 4,696,322, the spherical valve element is formed by two half-spherical hollow elements which are joined and welded together to form a unitary hollow sphere. An anti-siphon back flow preventer is welded to the inside wall of one of the half-spherical elements and is thereby fixedly attached to and is then sealed within the spherical valve element after the two half-spherical elements are welded together.
The back flow preventer includes a chamber in which is mounted a flapper valve for normally covering a plurality of apertures formed through one wall of the chamber. A large opening of the chamber is covered by a snap ring which is formed with a smaller central aperture to thereby capture the flapper valve within the chamber. The plurality of apertures communicates through openings in the spherical valve element with the atmosphere surrounding the faucet system.
When the associated water supply is subjected to a positive pressure, the flow of water through the valve element causes the flapper valve to cover and seal the plurality of apertures. When the water supply is subjected to a negative pressure, and the dispensing head of the faucet system is located within dirty water with the valve positioned to allow water to flow, the dirty water tends to flow in a reverse direction through the spherical valve element. This action would result in the mixing of the dirty water with the potable water of the water supply within the supply line. However, with the development of the negative pressure and the tendency of the dirty water to flow in the reverse direction, the flapper valve is drawn away from the apertures to allow atmospheric pressure to be applied within the spherical valve element. In this manner, the atmospheric pressure neutralizes the effects of the negative pressure whereby the reverse flow of dirty water is prevented.
While the back flow preventer of U.S. Pat. No. 4,696,322 is effective to prevent the undesirable reverse flow of dirty water as noted above, the preventer is welded in place within the hollow spherical valve element. Further, the valve element is formed by two half sections which are welded together to permanently seal the preventer within the valve element as noted above. So, not only is the preventer welded in place, it is contained within an enclosure, that is the welded spherical valve element. Thus, when replacement of a defective valve element is necessitated, another preventer will be required in the replacement valve element because the original preventer is welded and sealed within the defective valve. Further, if the preventer is defective and requires replacement, the entire valve element must be replaced because the defective preventer is welded and sealed within the valve element.
In addition, the preventer as mounted within the valve element is constantly being moved when the valve element is moved to initiate or stop the supply of water therethrough. This movement subjects the flapper valve and the snap ring to sudden and sometimes violent forces which could possibly jar the flapper valve or snap ring from their mountings resulting in defective operation of the preventer.
Thus, there is a need for an inexpensive vacuum breaker system which can be inserted or removed with relative ease from the associated fluid flow system independently of the valve of the fluid flow system. Further, there is a need for an inexpensive vacuum breaker system which can be mounted removably in a fixed position at all times, including during use of the related fluid flow system, and not be subjected to forces resulting from the manipulation of the related valve of the fluid flow system.